1. Field of the Invention
The present invention relates to a pattern formation method, a pattern formation apparatus, an exposure method, an exposure apparatus, and a device manufacturing method, more specifically to a pattern formation method and a pattern formation apparatus used to form patterns on an object, an exposure method and an exposure apparatus used to expose an object with an illumination light, and a device manufacturing method with the pattern formation method, the exposure method, or the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process for manufacturing electronic devices (micro devices) such as a semiconductor device and a liquid-crystal display element, a projection exposure apparatus (stepper) with a step-and-repeat method, a projection exposure apparatus (scanner) with a step-and-scan method, or the like which transfers a pattern formed on a mask (reticle, photomask, or the like) onto a plate (glass plate, wafer, or the like) coated with a photosensitive agent such as a resist via a projection optical system has been used.
Meanwhile, recently, a maskless-type exposure apparatus that is capable of forming devices without expensive masks, i.e., an exposure apparatus that uses a variable molding mask (called also an active mask or an image generator) with a plurality of modulation elements, which spatially individually modulate at least one of amplitude, phases and polarization of illumination lights without masks as an original plate with a fixed pattern, has been proposed (see, e.g., Kokai (Japanese Unexamined Patent Application Publication) No. 2004-327660). According to a maskless-type exposure apparatus described in Kokai (Japanese Unexamined Patent Application Publication) No. 2004-327660), by changing patterns generated on a variable pattern generation device (variable molding mask) in synchronous with scanning of a substrate stage, a desired pattern can be formed on a substrate held on the substrate stage. Moreover, since the apparatus does not need to be equipped with a mask stage unlike an exposure apparatus with a conventional mask, cost reduction and miniaturization of exposure apparatuses are made possible.
However, for the maskless-type exposure apparatus described above, it has been recently cleared to be difficult to obtain, particularly, a pattern with a size (i.e. line width) which is not equal to any of integer multiples of a size corresponding to that of the modulation elements at a desired position, since sizes and positions of modulation elements (e.g., mirrors, or the like) are fixed on the variable pattern generation device, not only for a transmissive type but also for a reflective type.